The f/stop and color balance of a color enlarger must be properly established to get consistent results in processing color negatives to provide the proper color print. To achieve this, there must be accurate analysis of the color of the light issuing from a color enlarger and also the density of the negatives which are to be printed with the use of the enlarger. In the past, attempts have been made to provide a control for these various parameters; however, the attempts have not always been completely satisfactory and, because of this drawback, a need has arisen for an improved controller which provides the necessary analysis and the control of the actuation of a color enlarger plus to provide consistently good results over long periods of operation time.